Crypto vaccine launched for 2025 calvers
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A vaccine against Cryptosporidium is available for the first time ever, for calvers in 2025.
Cryptosporidium parvum, commonly referred to as Crypto, is a one-celled parasitic organism that causes watery diarrhea in calves (as well as other mammals).
Helena Madden, Ruminant Veterinary Manager with Merck Sharp & Dohme (MSD) Animal Health, joined Stuart Childs on the latest Dairy Edge to discuss the new vaccine, Bovilis Cryptium.
“The thing that’s most likely to kill calves up to a month of age is going to be calf scour”, Helena said.
“Rotavirus and Crypto are going to account for the absolute majority of cases of calf scour”, she explained.
Both can cause serious scours, and there may well be a mixed infection, with both involved, causing a particularly severe scour.
Crypto eggs (oocysts), once ingested, invade and damage the cells lining the wall of the small intestine, preventing the calf from absorbing nutrients, and the calf may become weak and lethargic. The eggs undergo numerous multiplication stages before further infective oocysts are excreted in the faeces.
“These little eggs build up massively in the environment, but are also very resistant, so it’s quite hard to get rid of them”, Helena said. “We know that as few as 17 of these little eggs are enough to give the calf scour. But if you have a calf that has Crypto, they’ll be shedding billions of them every day, and they’ll shed for up to two weeks”.
Crypto infection in the calf can continue for a considerable period, as a proportion of the oocysts may exist in the intestine, which initiates an auto-infection cycle.
Helena cited research findings on the costs associated with scour. “An outbreak of scour in a 100-cow dairy herd, taking into account mortality, reduced growth rate, and the treatment costs of €8.71, was roughly working out at a cost of €67 per calf”, she said.
If calves get scour, the research indicates they may be 17 times more likely to get pneumonia, adding further to the costs, and potentially inhibiting their development over their lifetime.
Moreover, an outbreak of scour exerts a heavy toll in terms of extra farmer labour, at a busy time of year.
Cleaning, disinfection of sheds, and good management of calf sheds are vital to reduce the risks.
A Crypto outbreak in mid-February can pose great challenges in calf rearing. “The reality is, if there’s a little bit of Crypto lingering about, and the first few calves get it, they will start multiplying it”, Helena said. “Of course, there are lots of things you can do to minimise the risks. Hygiene is going to be massive. It’ll be spread in the faeces”.
In an outbreak situation, one has to concentrate on protecting the youngest calves. The sequence of feeding is one preventative measure, starting with the youngest and feeding the sick calves last. Farmers themselves can inadvertently move the oocysts from place to place.
Immunity can build up over time. “Older animals can get Crypto too, but hopefully, unless there’s something wrong with them, they’re not going to get sick with it, whereas the baby calf doesn’t have protection, and that’s where your vaccine comes in, to protect those baby calves”, Helena explained.
Teagasc recommends vaccination against Cryptosporidium as an investment in herd health.
“We’re vaccinating the cow in the period close to calving, in that 12 to three weeks window prior to calving”, Helena said.
Calves are born with no immunity to diseases, but they can quickly develop protection via the colostrum of a vaccinated mother. The quality of the colostrum depends on good nutrition of the pregnant cow, particularly adequate protein and energy, to complement the effectiveness of the vaccine.
The Bovilis Cryptium vaccine is the product of 23 years of research involving both human health and veterinary researchers co-operating.
It works by increasing the specific antibodies in the colostrum of the dam against Cryptosporidium parvum. These antibodies are then passed onto the calf. “As soon as that calf gets colostrum, gets that milk into them, they then have protection against the disease”, Helena explained.
The dosing regimen for the Bovilis Cryptium vaccine requires two doses under the skin 12 to three weeks before calving, and four to five weeks apart, with the second dose being given at least three weeks prior to calving. In the following years, a single booster dose is administered 12 to three weeks before each subsequent calving.
Helena said that following the initial Bovilis Cryptium shot (given perhaps in the last week of November), both the Bovilis Rotavec Corona vaccine (which protects the calf from diarrhoea caused by rotavirus, coronavirus, and E coli) and the Cryptium second shot can be administered at the same time, a month or five weeks later (typically in late December or in early January), at different vaccination sites on the cow, at least three weeks before calving.
The in-calf heifers in November 2025 will need the two shots of Bovilis Cryptium for their primary vaccination course, and the booster thereafter.
To maximise the effectiveness of the colostrum in protecting the calf against Cryptosporidium parvum, the 1-2-3, rule can be followed (use the first milk from the cow; feed the calf colostrum within the first two hours of birth; and calves must be offered at least 3 litres of good quality colostrum).
The colostrum should be given to the calf for at least five days, but may be given as long as possible, depending on the practicalities on the farm. “That milk is fantastic for calves”, Helena said.
